10. Patients with past uncontrolled seizures, central nervous system or psychological disorder which makes it impossible to provide informed consent and is so clinically significant as to interfere with oral medication 11. Uncontrolled active infection or sepsis 12. Deep vein thrombosis within 4 weeks prior to providing informed consent 13. Severe acute or chronic disease which may deteriorate the capability to participate in the study or make it difficult to interpret the study results 14. Not fully recovered from surgery 15. Patients who may have difficulty in absorbing orally administered study drug